RustPython
diff --git a/‎Lib/argparse.py
Copy file name to clipboardExpand all lines: Lib/argparse.py
+53-15Lines changed: 53 additions & 15 deletions b/‎Lib/argparse.py
Copy file name to clipboardExpand all lines: Lib/argparse.py
+53-15Lines changed: 53 additions & 15 deletions
@@ -89,6 +89,8 @@
 import re as _re
 import sys as _sys
 
+import warnings
+
 from gettext import gettext as _, ngettext
 
 SUPPRESS = '==SUPPRESS=='
@@ -151,6 +153,7 @@ def _copy_items(items):
 # Formatting Help
 # ===============
 
+
 class HelpFormatter(object):
     """Formatter for generating usage messages and argument help strings.
 
@@ -693,15 +696,27 @@ class ArgumentDefaultsHelpFormatter(HelpFormatter):
     """
 
     def _get_help_string(self, action):
+        """
+        Add the default value to the option help message.
+
+        ArgumentDefaultsHelpFormatter and BooleanOptionalAction when it isn't
+        already present. This code will do that, detecting cornercases to
+        prevent duplicates or cases where it wouldn't make sense to the end
+        user.
+        """
         help = action.help
-        if '%(default)' not in action.help:
+        if help is None:
+            help = ''
+
+        if '%(default)' not in help:
             if action.default is not SUPPRESS:
                 defaulting_nargs = [OPTIONAL, ZERO_OR_MORE]
                 if action.option_strings or action.nargs in defaulting_nargs:
                     help += ' (default: %(default)s)'
         return help
 
 
+
 class MetavarTypeHelpFormatter(HelpFormatter):
     """Help message formatter which uses the argument 'type' as the default
     metavar value (instead of the argument 'dest')
@@ -717,7 +732,6 @@ def _get_default_metavar_for_positional(self, action):
         return action.type.__name__
 
 
-
 # =====================
 # Options and Arguments
 # =====================
@@ -752,7 +766,7 @@ def __str__(self):
         if self.argument_name is None:
             format = '%(message)s'
         else:
-            format = 'argument %(argument_name)s: %(message)s'
+            format = _('argument %(argument_name)s: %(message)s')
         return format % dict(message=self.message,
                              argument_name=self.argument_name)
 
@@ -860,6 +874,7 @@ def format_usage(self):
     def __call__(self, parser, namespace, values, option_string=None):
         raise NotImplementedError(_('.__call__() not defined'))
 
+
 class BooleanOptionalAction(Action):
     def __init__(self,
                  option_strings,
@@ -879,9 +894,6 @@ def __init__(self,
                 option_string = '--no-' + option_string[2:]
                 _option_strings.append(option_string)
 
-        if help is not None and default is not None and default is not SUPPRESS:
-            help += " (default: %(default)s)"
-
         super().__init__(
             option_strings=_option_strings,
             dest=dest,
@@ -893,6 +905,7 @@ def __init__(self,
             help=help,
             metavar=metavar)
 
+
     def __call__(self, parser, namespace, values, option_string=None):
         if option_string in self.option_strings:
             setattr(namespace, self.dest, not option_string.startswith('--no-'))
@@ -941,7 +954,7 @@ class _StoreConstAction(Action):
     def __init__(self,
                  option_strings,
                  dest,
-                 const,
+                 const=None,
                  default=None,
                  required=False,
                  help=None,
@@ -1036,7 +1049,7 @@ class _AppendConstAction(Action):
     def __init__(self,
                  option_strings,
                  dest,
-                 const,
+                 const=None,
                  default=None,
                  required=False,
                  help=None,
@@ -1168,6 +1181,13 @@ def add_parser(self, name, **kwargs):
 
         aliases = kwargs.pop('aliases', ())
 
+        if name in self._name_parser_map:
+            raise ArgumentError(self, _('conflicting subparser: %s') % name)
+        for alias in aliases:
+            if alias in self._name_parser_map:
+                raise ArgumentError(
+                    self, _('conflicting subparser alias: %s') % alias)
+
         # create a pseudo-action to hold the choice help
         if 'help' in kwargs:
             help = kwargs.pop('help')
@@ -1648,6 +1668,14 @@ def _remove_action(self, action):
         super(_ArgumentGroup, self)._remove_action(action)
         self._group_actions.remove(action)
 
+    def add_argument_group(self, *args, **kwargs):
+        warnings.warn(
+            "Nesting argument groups is deprecated.",
+            category=DeprecationWarning,
+            stacklevel=2
+        )
+        return super().add_argument_group(*args, **kwargs)
+
 
 class _MutuallyExclusiveGroup(_ArgumentGroup):
 
@@ -1668,6 +1696,14 @@ def _remove_action(self, action):
         self._container._remove_action(action)
         self._group_actions.remove(action)
 
+    def add_mutually_exclusive_group(self, *args, **kwargs):
+        warnings.warn(
+            "Nesting mutually exclusive groups is deprecated.",
+            category=DeprecationWarning,
+            stacklevel=2
+        )
+        return super().add_mutually_exclusive_group(*args, **kwargs)
+
 
 class ArgumentParser(_AttributeHolder, _ActionsContainer):
     """Object for parsing command line strings into Python objects.
@@ -1857,8 +1893,7 @@ def parse_known_args(self, args=None, namespace=None):
         if self.exit_on_error:
             try:
                 namespace, args = self._parse_known_args(args, namespace)
-            except ArgumentError:
-                err = _sys.exc_info()[1]
+            except ArgumentError as err:
                 self.error(str(err))
         else:
             namespace, args = self._parse_known_args(args, namespace)
@@ -1962,7 +1997,11 @@ def consume_optional(start_index):
                     # arguments, try to parse more single-dash options out
                     # of the tail of the option string
                     chars = self.prefix_chars
-                    if arg_count == 0 and option_string[1] not in chars:
+                    if (
+                        arg_count == 0
+                        and option_string[1] not in chars
+                        and explicit_arg != ''
+                    ):
                         action_tuples.append((action, [], option_string))
                         char = option_string[0]
                         option_string = char + explicit_arg[0]
@@ -2133,8 +2172,7 @@ def _read_args_from_files(self, arg_strings):
                                 arg_strings.append(arg)
                         arg_strings = self._read_args_from_files(arg_strings)
                         new_arg_strings.extend(arg_strings)
-                except OSError:
-                    err = _sys.exc_info()[1]
+                except OSError as err:
                     self.error(str(err))
 
         # return the modified argument list
@@ -2484,9 +2522,9 @@ def _get_value(self, action, arg_string):
             result = type_func(arg_string)
 
         # ArgumentTypeErrors indicate errors
-        except ArgumentTypeError:
+        except ArgumentTypeError as err:
             name = getattr(action.type, '__name__', repr(action.type))
-            msg = str(_sys.exc_info()[1])
+            msg = str(err)
             raise ArgumentError(action, msg)
 
         # TypeErrors or ValueErrors also indicate errors